This invention relates to combining plural laser beams coherently.
Individual semiconductor lasers are currently limited in output power by either catastrophic facet damage or heat build up. Linear arrays of lasers have been developed that produce higher power by combining many individual lasers. Monolithic surface emitting geometries allow laser arrays to be constructed in two dimensions as well. In addition to high power, however, many applications also require a source with high brightness, or power per unit area per unit solid angle. High brightness requires mutual coherence among the individual lasers. In addition, the individual beams must be combined to produce a single lobed, far-field pattern with negligible side lobes. The present invention establishes mutual coherence among lasers and combines their outputs to generate a single lobed, far-field pattern.